MMP9 and Bloom syndrome: As shown in Fig 5C–E, quantitative real‐time PCR (qPCR) analysis of profibrotic markers in the BALF macrophages revealed that Arg1 (Grasemann et al, 2015), MMP9 (Kui Tan et al, 2013), and TIMP3 (García‐Alvarez et al, 2006) were all elevated in BLM‐induced mice relative to controls.